1. Field of the Invention
The present invention relates to an epoxy resin composition having excellent moldability and good adhesion so that it may be moldable over semiconductor devices for encapsulation without voids and other defects. It relates as well to a semiconductor device encapsulated in a cured form of the epoxy resin composition.
2. Prior Art
Biphenyl epoxy resins have come into use recently in a field of molding of semiconductor devices because they improve the solder reflow resistance of epoxy resin compositions. These epoxy resins are also a favorite choice today because their crystallinity and low viscosity allow the high loading of inorganic filler, which in turn ensures minimized moisture absorption, and because they firmly adhere to various types of substrates.
However, biphenyl epoxy resins have some drawbacks. Because of their high crystallinity, they tend to deposit out as crystals when kneading is inadequate. Moreover, molten biphenyl epoxy resins have so low viscosity that little shearing forces would be applied during kneading, resulting in short kneading. As a result, molded parts often have voids at the interior and are thus less reliable. Solutions to these problems have been awaited.